Method and apparatus for controlling semi-persistent scheudling

ABSTRACT

A communication system configures a plurality of sidelink (SL) Semi-Persistent Scheduling (SPS) for a user device. In some embodiments, a method includes generating, by a base station, SL SPS configuration information for the user device, wherein the SL SPS configuration information comprises: an SL SPS radio network temporary identifier (RNTI) for the user device; and SL SPS index information to indicate a plurality of SL SPS configurations for the user device. The method further includes configuring a radio resource control (RRC) message comprising the SL SPS configuration information and transmitting, by the base station and to the user device, the RRC message.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean PatentApplication No. 10-2016-0102422, filed on Aug. 11, 2016, which is herebyincorporated by reference in its entirety.

BACKGROUND 1. Field

The present disclosure relates to a wireless communication system, andmore particularly, to a method and apparatus for semi-persistentscheduling for vehicle-to-everything (V2X).

2. Discussion of the Background

Vehicle-to-everything (vehicle-to-X: V2X) communication refers to acommunication scheme that is capable of 1) providing general wirelesscommunication service, such as voice calls, data transmission, and thelike, and 2) exchanging or sharing information during driving, such astraffic conditions or the like, through communication with othervehicles, pedestrian-based wireless terminals such as smart phones, orinfrastructures such as a mobile communication network or a wirelesscommunication device installed in a roadway. V2X may includevehicle-to-vehicle (V2V) indicating communication between terminalscarried by vehicles, vehicle-to-pedestrian (V2P) indicatingcommunication between terminals carried by a vehicle and an individual,and vehicle-to-infrastructure/network (V2I/N) indicating communicationbetween a vehicle and a roadside unit (RSU)/network. In this lastinstance, the RSU may be a transportation infrastructure entity embodiedby a fixed terminal or a base station. For example, it may be an entitythat transmits a speed notification to a vehicle.

Technologies which are additionally required by the current LTE systemand a next-generation wireless communication system are currentlydiscussed based on performance requirements for supporting V2X in theLTE system and the next generation wireless communication system. Alsounder discussion is a semi-persistent scheduling (SPS) scheme thatefficiently supports periodic data transmission; this scheme is requiredfor supporting a vehicle communication service, and a plurality of SPSconfigurations. However, an SPS activation and deactivation scheme forsupporting a plurality of SPS configurations has not yet beendetermined.

SUMMARY

An example embodiment of the present disclosure describes a method ofsupporting sidelink (SL) semi-persistent scheduling (SPS) of a userequipment (UE) by an evolved node B (eNB) in a wireless communicationsystem. The method may include transmitting, to the UE, informationassociated with a plurality of SL SPS configurations to be configuredfor the UE; and transmitting, to the UE, SL SPS-related controlinformation for each of one or more SL SPS configurations out of theplurality of SL SPS configurations.

An example embodiment of the present disclosure describes a method ofperforming sidelink (SL) semi-persistent scheduling (SPS)transmission/reception by a UE in a wireless communication system. Themethod may include: receiving, from an eNB, information associated witha plurality of SL SPS configurations to be configured for the UE; andreceiving, from the eNB, SL SPS-related control information for each ofone or more SL SPS configurations out of the plurality of SL SPSconfigurations.

Descriptions provided below may be applied, individually or incombination, to embodiments provided according to various aspects of thepresent invention.

The information associated with the plurality of SL SPS configurationsmay include identification information for each of the plurality of SLSPS configurations.

The SL SPS-related control information may include identificationinformation for each of one or more SL SPS configurations.

The SL SPS-related control information may further include activation ordeactivation indication information associated with a predetermined SLSPS configuration or with SL grant information associated with thepredetermined SL SPS configuration.

The SL SPS-related control information may be transmitted through aMedium Access Control (MAC) Control Element (CE) or through the DownlinkControl Information (DCI) of a Physical Downlink Control Channel (PDCCH)or an Enhanced PDCCH (EPDCCH).

The identification information may be a Radio Network Temporary Identity(SPS SL-RNTI) or an SL_SPS_Index.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating a wireless communication systemto which the present invention is applied.

FIGS. 2 through 7 are diagrams illustrating vehicle communication in awireless communication system to which the present invention is applied;

FIG. 8 is a diagram illustrating a semi-persistent resource schedulingmethod for a sidelink in a wireless communication system to which thepresent invention is applied;

FIG. 9 is a diagram illustrating a method of scheduling asemi-persistent resource for a sidelink by an evolved node B (eNB)according to an embodiment of the present invention;

FIG. 10 is a diagram illustrating a method of scheduling asemi-persistent resource for a sidelink by an eNB according to anotherembodiment of the present invention;

FIG. 11 is a diagram illustrating the operation of reporting userequipment (UE) assistance information according to the presentinvention;

FIGS. 12 to 16 are diagrams illustrating the configuration of a MAC PDUaccording to the present invention;

FIG. 17 is a flowchart illustrating the operations of an eNB and a UEaccording to the present invention; and

FIG. 18 is a diagram illustrating the configuration of a wireless deviceaccording to the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Example embodiments of the present invention will be described morefully hereinafter, with reference to the accompanying drawings whichshow the example embodiments of the invention. Throughout the drawingsand the detailed description, unless otherwise described, the samedrawing reference numerals are understood to refer to the same elements,features, and structures. In describing the example embodiments,detailed descriptions of known configurations or functions may beomitted for clarity and conciseness.

Further, the description herein is related to a wireless communicationnetwork. One or more operations in a wireless communication network maybe performed in a process of controlling a network and transmitting databy a system that controls the wireless network (e.g., a base station),or may be performed in a user equipment communicating with the wirelesscommunication network.

In a network system including a plurality of network nodes, e.g., a basestation, various operations for facilitating a communication with amobile device or various operations for communicating with a mobiledevice may be performed by a base station or other network nodes in thenetwork system. The base station (BS) may be referred to as a fixedstation, Node B, Evolved Node B (eNB), an access point (AP), etc. Amobile terminal may be referred to as a mobile device, user equipment(UE), a mobile station (MS), a mobile subscriber station (MSS), asubscriber station (SS), non-access point station (non-AP STA), etc.

FIG. 1 is a block diagram illustrating a wireless communication system.

The network structure illustrated in FIG. 1 may be a network structureof an Evolved-Universal Mobile Telecommunications System (E-UMTS). TheE-UMTS system may include a Long-Term Evolution (LTE) system, anLTE-Advanced (LTE-A) system, a 3rd Generation Partnership Project (3GPP)Standard-based network structure which satisfies the InternationalMobile Telecommunication-2020 (IMT-2020) standard defined by theInternational Telecommunication Union-Radio communication sector(ITU-R), or the like.

Referring to FIG. 1, a wireless communication system 10 may provide acommunication service between a base station (BS) and a user equipment(UE). In a wireless communication system, a UE and a BS may wirelesslytransmit and receive data. Also, the wireless communication system maysupport Device-to-Device (D2D) communication between UEs. A wirelesscommunication system that supports D2D communication will be describedlater.

The BS 11 of the wireless communication system 10 may provide acommunication service to a UE existing within the transmission coverageof the BS 11, through a predetermined frequency band. The coverage rangewithin which a BS provides a service is also referred to as a site. Thesite may include various areas 15 a, 15 b, and 15 c, which may bereferred to as sectors. The sectors included in the site may havedifferent identifiers, respectively, so that each sector can beidentified by its own sector identifier. Each sector 15 a, 15 b, and 15c may be construed as a part of the area that the BS 11 covers.

ABS 11 communicates with UE 12. BS 11 may be referred to as eNB(evolved-NodeB), BTS (Base Transceiver System), Access Point, femto basestation, Home nodeB, relay and Remote Radio Head (RRH).

A user equipment 12 (mobile station, MS) may be stationary or mobile,and may also be referred to using different terms, including UE (userequipment), MT (mobile terminal), UT (user terminal), SS (subscriberstation), wireless device, PDA (personal digital assistant), wirelessmodem, handheld device, or connected car.

A base station 11 can be also referred a cell, which inclusively isreferred to various coverage areas, such as mega cell, macro cell, microcell, pico cell, and femto cell. A cell may be used as a term forindicating a frequency band that a BS provides, a coverage of a BS, or aBS. Further, the base station 11 may include different types of basestations and different terms may be used to distinguish the differenttype of base stations from each other. For example, in a dualconnectivity configuration where one mobile terminal is connected to twoor more base stations, the base station 11 may include at least twotypes of base stations, a master eNodeB and a secondary eNodeB. Themaster eNodeB (MeNB) is capable of controlling radio resource controlconnection, by directly transmitting radio resource control connectionsignaling to a UE, and controlling mobility of the UE including ahandover process. The secondary eNodeB (SeNB), which may not have theabove capabilities of the MeNB, provides the UE with additional radioresource and performs partial radio resource control for the UE whileother radio resource controls are performed by an MeNB.

Hereinafter, the term downlink refers to communication from a BS 11 to aUE 12, and the term uplink refers to communication from a UE 12 to a BS11. For a downlink, a transmitter may be part of a BS 11, and a receivermay be part of a UE 12. For an uplink, a transmitter may be part of a UE12 and a receiver may be part of a BS 11.

There is no limitation in the multiple access method applied to awireless communication system. Diverse methods can be used, includingCDMA (Code Division Multiple Access), TDMA (Time Division MultipleAccess), FDMA (Frequency Division Multiple Access), OFDMA (OrthogonalFrequency Division Multiple Access), SC-FDMA (Single Carrier-FDMA),OFDM-FDMA, OFDM-TDMA, and OFDM-CDMA. Uplink transmission and downlinktransmission can use either TDD (Time Division Duplex), which usesdifferent time locations for transmissions, or FDD (Frequency DivisionDuplex), which uses different frequencies for transmissions.

Abbreviations used in the present disclosure are defined as follows:

D2D: Device to Device (communication)

ProSe: (Device to Device) Proximity Services

V2X: Vehicle to X (everything)

V2V: Vehicle to Vehicle

V2P: Vehicle to Pedestrian

V21/N: Vehicle to Infrastructure/Network

GNSS: Global Navigation Satellite System

RSU: Road Side Unit

SL: Sidelink

SCI: Sidelink Control Information

PSSCH: Physical Sidelink Shared Channel

PSBCH: Physical Sidelink Broadcast Channel

PSCCH: Physical Sidelink Control Channel

PSDCH: Physical Sidelink Discovery Channel

Also, various operation modes may be defined based on a resourceallocation scheme for a direct link (e.g., D2D, ProSe, or SLcommunication). Data and control information for direct link (e.g., D2D,ProSe, or SL) communication are called direct data and direct controlinformation, respectively.

Mode 1 indicates an operation mode in which a UE reports the amount ofdata to be transmitted through a direct link for transmitting directdata and direct control information to an evolved node B (eNB) through alink between the UE and the eNB, and the eNB (or a relay) accuratelyschedules a resource to be used by the UE through the direct link basedon the information reported through the link between the UE and the eNB.Mode 2 indicates an operation mode in which the UE autonomously selectsa resource to transmit direct data and direct control information from acurrently available resource pool, based on either information that isstored in advance in a USIM or a memory in the UE or on informationobtained by receiving system information from the eNB.

Here, the resource pool includes some of the available radio resourcesof an eNB (or a device having management authority for the radioresources in a network) by taking into consideration the available radioresources such as available time, frequency, space, code, or the likedefined in a wireless communication system for direction controlinformation and data transmission. A resource unit for each bit isdefined using a bitmap to indicate the resource pool. A resourcecorresponding to a part marked with ‘1’ is included in the correspondingresource pool. The location of a resource indicated by the bitmap, andthe bitmap is repetitively provided by a network, e.g., BS 11.

Hereinafter, although embodiments of the present invention are describedby using V2X communication as an example, the scope of the presentinvention may not be limited to V2X communication. Further, theembodiments of the present invention may be applied to direct link basedcommunication, such as D2D, ProSe, SL communication, or the like.

V2X is a term that generally indicates V2V, V2P, and V2I/N, and each ofV2V, V2P, and V2I/N may be defined as below in association with LTEcommunication or a next generation mobile communication system.

-   -   V2V (Vehicle-to-Vehicle)

V2V covers LTE-based or next generation mobile communicationsystem-based communication between vehicles. That is, V2V may be definedas LTE-based or next generation mobile communication system-basedcommunication between vehicles.

-   -   V2P (Vehicle-to-Pedestrian)

V2P covers LTE-based or next generation mobile communicationsystem-based communication between a vehicle and a device carried by anindividual (e.g., portable terminal carried by a pedestrian, a cyclist,a driver, or a passenger). That is, V2P may be defined as LTE-based ornext generation mobile communication system-based communication betweena vehicle and an individual.

-   -   V2I/N (Vehicle-to-Infrastructure/Network)

V2I/N covers LTE-based or next generation mobile communicationsystem-based communication between a vehicle and a roadsideunit/network. A roadside unit (RSU) may be a transportationinfrastructure entity (e.g., an entity that transmits a speednotification) embodied by a fixed UE or an eNB. V2I may indicatecommunication between a vehicle and a server, and V2N may indicatecommunication between a vehicle and an eNB. However, they may not belimited thereto, and may be commonly called V2I/N.

For a V2V operation based on PC5 which is a D2D communication link(i.e., a direct interface between two devices), various scenarios areconsidered as follows.

(Type 1) An Operation Band Used as Test Points for Evaluation

Case 1A: 6 GHz

Case 1B: 2 GHz

Other frequency bands may be considered, in addition to the above cases.For example, one of the ISM bands may be used. Alternatively, one of thecommon frequencies that are operable in the LTE and the next generationmobile communication system, used commonly all over the world, may beconsidered.

(Type 2) An eNB Disposition Including the Probability of Network Control

Case 2A: autonomous resource allocation by a mode 2 UE based onsemi-statically network configured/pre-configured wireless parameters

Case 2B: a larger number of UE-specific and/or dynamic resourceallocations provided by eNBs, including mode 1, that is distinct fromCase 2A

(Type 3)

Case 3A: UEs perform communication based on PC5 that uses a singlecarrier

Case 3B: UEs perform communication based on PC5 that uses multiplecarriers

(Type 4)

Case 4A: operation by a single operator

Case 4B: a set of PC5-based carriers shared by UEs that subscribe todifferent operators. This indicates that UEs belonging to differentoperators are capable of transmitting a signal on the same carrier.

Case 4C: operators are allocated to different carriers. This indicatesthat a UE is capable of transmitting a signal only on a carrierallocated to the operator that the UE belongs to.

(Type 5) Existence Together With Uu (An Interface Between an eNB and aUE)

Case 5A: a V2X-dedicated carrier is operated. Here, uplink traffic doesnot exist in the Uu interface on a PC5-based carrier.

FIGS. 2 through 7 are diagrams illustrating vehicle communication in awireless communication system to which the present invention is applied.

For V2X, only a PC5 link (which is a link between UEs defined for D2D orProSe) may be considered as shown in FIG. 2. The PC5 link may be definedas a sidelink (SL).

Alternatively, only a Uu link, which is a link between an eNB and a UE,may be considered as illustrated in FIG. 3. Alternatively, a road sideunit (RSU) in the form of a UE is included, and both the PC5 link andthe Uu link may be considered as illustrated in FIGS. 4 and 5.

Hereinafter, a UE includes the concept of a UE used by a general user,such as a smart phone and the like, and a UE contained in a vehicle.

D2D communication refers to a technology in which UEs directly receiveand transmit data. Hereinafter, it is assumed that a UE disclosed inembodiments of the present invention supports D2D communication. Also,D2D communication may be interchangeably used with an expression, ProSeor ProSe-D2D communication. The use of the term “ProSe” for D2Dcommunication may not change the meaning of direct datatransmission/reception between UEs, but may add the meaning of aproximity-based service. Also, a radio interface and/or wirelesscommunication link between UEs that perform D2D communication is definedas a sidelink (SL).

D2D communication performs 1) a discovery process for communicationbetween UEs existing inside a network coverage (in-coverage (INC)) oroutside the coverage (out-of-coverage (OCC)); and 2) a directcommunication process for transmitting and receiving control data and/ortraffic data between UEs. Hereinafter, a UE that transmits a signalbased on D2D communication is referred to as a transmission UE (Tx UE),and a UE that receives a signal based on D2D communication is referredto as a reception UE (Rx UE). A Tx UE may transmit a discovery signal,and an Rx UE may receive a discovery signal. A Tx UE and an Rx UE mayexchange their roles. A signal transmitted by a Tx UE may be received bytwo or more Rx UEs.

D2D communication may be used for various purposes. For example, withina commercial frequency-based network coverage site, D2D communicationmay be used for public safety, traffic network services, ultra-lowlatency services, commercial services, and the like. However, D2Dcommunication based on a traffic network-dedicated frequency may be usedonly for traffic network communication, traffic safety, and the like,irrespective of network coverage.

When UEs located close to one another execute D2D communication in acellular system, loads on an eNB may be dispersed. Also, when UEslocated close to one another perform D2D communication, the UEs transmitdata within a relatively short distance and thus, the transmission powerconsumption and transmission latency of the UEs may be decreased. Inaddition, from the perspective of the whole system, existingcellular-based communication and D2D communication use the sameresources and thus, frequency usage efficiency may be improved when theydo not overlap spatially.

D2D communication may be classified as communication between UEsexisting within a network coverage (or eNB coverage) range (in-coverage(INC)), communication between UEs outside the coverage range(out-of-coverage (OOC)), and communication between a UE inside thenetwork coverage range and a UE outside the network coverage range.

An eNB schedules resources required when in-coverage UEs transmit datathrough a sidelink for D2D communication in a wireless communicationsystem. In this instance, the in-coverage UEs may report the amount ofdata (e.g., D2D data), which exists in a buffer of each UE and is to betransmitted through a sidelink to the eNB through a buffer status report(BSR). The BSR associated with the sidelink may be referred to as an SLBSR or a ProSe BSR, which is distinct from a BSR associated with a widearea network (WAN), such as the LTE system or a next generation mobilecommunication system. Also, although V2X is similar to D2D, a BSRspecific to D2D for V2X may be defined separately, which may be referredto as V2X BSR, so that the BSR may be distinguished from the SL BSR interms of service.

According to an embodiment of performing D2D communication, an eNB maytransmit D2D resource allocation information to a first UE located inthe coverage of the eNB. The D2D resource allocation information mayinclude allocation information associated with a transmission resourceand/or a reception resource, which may be used for D2D communicationbetween the first UE and another UE. The first UE that receives the D2Dresource allocation information from the eNB may transmit to the otherUE the D2D resource allocation information associated with a D2Dresource through which the D2D data is to be transmitted, so that theother UE may receive the D2D data transmitted by the first UE.

The first UE, a second UE, a third UE, and/or a fourth UE may performD2D communication based on D2D resource allocation information.Particularly, the second UE, the third UE, and/or the fourth UE mayobtain information associated with the first UE's D2D communicationresource. The second UE, the third UE, and/or the fourth UE may receiveD2D data transmitted from the first UE through a resource indicated bythe information associated with the first UE's D2D communicationresource. In this instance, the first UE may transmit informationindicating the amount of D2D data that exists in the first UE's bufferto the eNB through an SL BSR, in order to receive a resource for D2Dcommunication with the second UE, the third UE, and/or the fourth UEfrom the eNB.

Referring to FIG. 6, a first UE (V2X UE1) and a second UE (V2X UE2) arelocated in a network coverage (INC) range and they are capable ofperforming communication with an eNB (E-UTRAN). That is, the first UE(V2X UE1) and the second UE (V2X UE2) may perform datatransmission/reception for a vehicle communication service through aneNB (or Uu interface). In other words, the first UE (V2X UE1) and thesecond UE (V2X UE2) may mutually transmit and receive data for a vehiclecommunication service through a UL data transmission and a DL datareception. However, because a third UE (V2X UE3) and a fourth UE (V2X UE4) are located outside the network coverage (OOC) range, when they arelocated somewhere that does not allow D2D communication with the firstUE (V2X UE1) and the second UE (V2X UE2), they may not transmit andreceive data for a vehicle communication service to/from the first UE(V2X UE1) and the second UE (V2X UE2). A UE is incapable of performingcommunication with another UE, an eNB, a server, and the like which arelocated in an area where a signal cannot reach physically.

However, when the fourth UE (V2X UE4) outside the network coverage rangeneeds to access the network for a vehicle communication service, acommercial service, or the like, and D2D communication with a UE-typeRSU existing in the network service range is allowed through D2Dcommunication, the UE-type RSU acts as a relay, and thus, the fourth UE(V2X UE4) outside the network coverage range may transmit and receivedata to/from an eNB through an indirect route. That is, as illustratedin FIG. 4, the UE-type RSU acts as a relay, the fourth UE (V2X UE4)transmits vehicle communication service data to the UE-type RSU throughan SL, and the UE-type RSU may transfer the vehicle communicationservice data to the eNB using a UL transmission through the Uuinterface. The UEs (e.g., the first UE and the second UE) in the networkcoverage range may receive the fourth UE's vehicle communication servicedata (V2X UE4) through a downlink of the Uu interface. UEs (e.g., thethird UE and the fourth UE) that are capable of performing D2Dcommunication with the UE-type RSU and that exist outside the networkservice range may transfer the fourth UE's vehicle communication servicedata (V2X UE4) to the UEs (first UE and the second UE) existing withinthe network service range through the UE-type RSU.

As illustrated in FIG. 7, the vehicle communication service data thatthe fourth UE (V2X UE4) transfers to the UE-type RSU may be transferreddirectly to UEs (e.g., the third UE) that are capable of performing D2Dcommunication with the UE-type RSU and that exist outside the networkservice range although they are located somewhere D2D communication withthe fourth UE (V2X UE4) is not allowed. A V2X service is sensitive to adelay time, and thus, may reduce the delay time that occurs while theUE-type RSU receives data again from an eNB after the UE-type RSUpreferentially transfers data to the eNB for the transfer. Therefore,the UE-type RSU may prepare for the transmission of data received fromthe fourth UE to the eNB through the Uu interface (i.e., LTE uplink),and may prepare for the transmission of data to the third UE (V2X UE3)through an SL. Therefore, when the UE-type RSU operates in a mode inwhich an SL resource is controlled by the eNB, the UE-type RSU mayhandle vehicle communication service data received from the fourth UE(V2X UE4) as data to be included in an LTE-side BSR, and maysimultaneously handle the same as data to be included in an SL BSR. Thatis, the UE-type RSU may deliver the vehicle communication service datareceived from the forth UE (V2X UE4) to a Packet Data ConvergenceProtocol (PDCP) layer in an LTE-side radio bearer (RB) and a Radio LinkControl (RLC) layer, and at the same time, may deliver the sameinformation to a PDCP/RLC layer in an SL-side RB.

Here, the ProSe Priority per Packet (PPPP) of data delivered to theSL-side RB may maintain the priority of the received packet. When anSL-side RB that is mapped to the priority of the received packet doesnot exist, the UE-type RSU may autonomously configure a new RB thatsupports the priority and transmits the packet.

Hereinafter, a method of optimizing the utilization of radio resourcesis provided to overcome a problem occurring by the operation of SLSemi-Persistent Scheduling (SPS). The SPS is configured to reduce thedelay time caused by an SL BSR-based resource allocation scheme when anRSU and UEs for vehicle communication operate based on mode 1 in whichthey are controlled by an eNB, including the situation that has beendescribed in FIG. 7. More particularly, when two or more SL SPSs areconfigured and a plurality of SL SPSs corresponding to some or all ofthe two or more configured SL SPSs are activated, a method and apparatusfor operating the SL SPS of the present invention will be described.Here, if a serving cell supports SL communication, the SL SPS mayoperate irrespective of a primary serving cell and a secondary servingcell.

FIG. 8 is a diagram illustrating a semi-persistent resource schedulingmethod for a sidelink in a wireless communication system to which thepresent invention is applied.

In mode 1, for SL SPS vehicle communication, an eNB configures theSPS-config for an SL through a Radio Resource Control (RRC) message andoperates a separate resource allocation scheme for the SPS. TheSPS-config for an SL includes configuration information used when a UEperforms SL data transmission based on a radio resource allocatedthrough SL SPS, or may be simply referred to as an SL SPS configuration.Also, the eNB may configure a plurality of pieces of RRC layerinformation (e.g., SPS-config for an SL or an SL SPS configuration) fora vehicle's SL SPS transmission, and may operate a separate SPS resourceallocation scheme for each SL SPS configuration.

The transmission through SL SPS may be limited to a broadcast scheme.That is, vehicle communication data may be transmitted through SL SPSaccording to a broadcast scheme.

In some embodiments, a semi-persistent resource scheduling interval fora sidelink (semiPersistSchedIntervalSL) may be always set to ‘1’.Therefore, this may not be included in RRC configuration information.

Referring to FIG. 8, in association with a Sidelink Control (SC) periodnumber, an SC period that starts after an offset value, which defines astart point of the SC period based on subframe number 0 in System FrameNumber (SFN) 0, is defined as SC period number 0 810; an SC periodnumber increases by 1 from SC period number 0. The offset value may bedefined based on a subframe unit. The SC period number becomes 0 againafter an SC period number having the maximum number 820. The SFN may beone of the values in the range of 0 to 1023, and the subframe number maybe one of the values in the range of 0 to 9.

Based on radio resources allocated by SL SPS for a vehicle communicationservice, the eNB may determine configuration information for an SL datatransmission with respect to each UE or UE-type RSU through an RRCmessage (e.g., an RRC reconfiguration message).

FIG. 9 is a diagram illustrating a method of scheduling asemi-persistent resource for a sidelink by an eNB according to anembodiment of the present invention.

As an example, “implicitReleaseAfterSL” may be defined as the maximumnumber of consecutive empty transmission SC periods that do not includeSL transmission data for releasing an SPS configuration. A sidelinkdirect communication resource pool is configured on a semi-static basisusing the layer 3 SL-CommResourcePool RRC message as defined in 3GPPTS36.331. The layer 1 physical resources, e.g., resource blocks andsubframes, associated with the pool are partitioned into a sequence ofrepeating time periods, the sidelink control (sc) periods. Each scperiod is a time period consisting of transmission of sideline controlinformation (SCI) and its corresponding data. SCI includes the sidelinkscheduling information, such as resource block assignment, modulationand coding scheme, group destination ID for sidelink communication, etc.

FIG. 9 shows how an SL grant configured by SL SPS may be released asshown in the diagram 940. First, a UE receives a Physical DownlinkControl Channel (PDCCH) or Enhanced PDCCH (EPDCCH) indicating SL SPSactivation, or receives a MAC Control Element (CE) indicating SL SPSactivation whereby resources for SL SPS are allocated (that is, an SLgrant is configured). Then, empty transmission occurs in consecutive SCperiods, as many times as the maximum number defined by an eNB in allsubframes of the SC periods. That is, when an SC period 920 includingonly the case 910 in which only Medium Access Control Protocol DataUnits (MAC PDUs) (the new data including zero MAC Service Data Unit(SDU)) are generated, consecutively occurs as many times as the number930 defined in ‘implicitReleaseAfterSL’ (two times in FIG. 9), the SLgrant configured by SL SPS may be released as shown in the diagram 940.The SL grant release may be referred to as SL SPS deactivation. Here,the empty transmission is not actually transmitted through a PhysicalSidelink Shared Channel (PSSCH). That is, when a MAC PDU (which is newdata including zero MAC SDU) is configured in an MAC layer, the MAClayer does not transmit the MAC PDU to a physical layer. The zero MACSDU indicates transmission of nothing when data (e.g., an RLC SDU)transferred from an RLC layer to an MAC layer does not exist (that is,when no data to be transferred exists) and the MAC layer is in asituation to send only a MAC sub-header without data.

FIG. 10 is a diagram illustrating a method of scheduling asemi-persistent resource for a sidelink by an eNB according to anotherembodiment of the present invention.

As another example, “implicitReleaseAfterSL” may be defined as themaximum number of consecutively omitted MAC PDU transmissions that donot include SL transmission data for cancelling an SPS configuration.

Referring to FIG. 10, after a UE receives either a PDCCH/EPDCCHindicating SL SPS activation or an MAC CE indicating SL SPS activation,when empty transmission occurs consecutively as many times as themaximum number defined by an eNB, that is, when MAC PDUs (i.e. new dataincluding zero MAC SDU) are generated, an SL grant configured by SL SPSmay be released. Here, the empty transmission may not be actuallytransmitted through a PSSCH. That is, when a MAC PDU is configured in anMAC layer, the MAC PDU is not transmitted to a physical layer.

In the MAC layer, an actual MAC PDU is configured based on atransmittable information bit length provided from the physical layer.The transmittable information bit length may be calculated inconsideration of subframes in at least one available Time ResourcePattern for Transmission (T-RPT). For example, when four transmissionopportunities exist, the length of information bit that is capable oftransmitting a single MAC PDU may be calculated. When two transmissionopportunities exist in a single T-RPT, a time resource 1010 of twoT-RPTs is required for a single MAC PDU transmission. When the value of‘implicitReleaseAfterSL’ is set to 2 as shown in the diagram 1020, twoT-RPT durations may be counted as one duration as shown in the diagram1030. Therefore, SL SPS may be released when two MAC PDUs areconsecutively generated as new data including zero MAC SDU during fourconsecutive T-RPT durations, as shown in the diagram 1030 and 1040. Thatis, an SL grant configured by SL SPS may be released as shown in thediagram 1050. Here, T-RPT defines resources in the form of a patternbased on some periods, which are defined as the entire T-RPT durationfrom among subframes that an eNB sets as SL communication-allowedsubframes. As an example, the entire T-RPT duration may be eight SLcommunication-enabled subframes. The T-RPT may include an entireduration value, the number of resources that are actually allocated tothe entire duration, and information associated with a location of anactually allocated resource. As an example, a resource location may bedefined based on a bitmap scheme. ‘0’ indicates non-allocation and ‘1’indicates allocation. Time increases in a direction from the leftmostbit to the rightmost bit. In the above embodiments, when‘implicitReleaseAfterSL’ is not configured by an eNB, a UE determines‘implicitReleaseAfterSL’ to be ‘1’. Alternatively, when MAC PDUs, whichare new data including zero MAC SDU, are generated, a UE immediatelyreleases an SL grant without performing a counting operation associatedwith an ‘implicitReleaseAfterSL’ field. In association with an SL SPSoperation defined as described above, the embodiments of the presentinvention will describe a method of supporting a plurality of SL SPSconfigurations with respect to a single UE.

A new method for individually indicating activation and deactivation ofa plurality of SL SPS configurations of a single UE will be described asfollows. Second, a new method for individually configuring or releasingSL grants with respect to a plurality of SL SPS configurations of asingle UE will be described. Third, to provide control information forindividual activation and deactivation of a plurality of SL SPSconfigurations of a single UE and/or to provide control information forconfiguring and releasing SL grants, a method of using a PDCCH/EPDCCHDCI and a new method of using a MAC control element (CE) will bedescribed. Fourth, when a plurality of SL SPS configurations may existfor a single UE but the plurality of SL SPSs are not allowed to beactivated at the same time, a new method for providing controlinformation for SLS SPS activation and deactivation and/or controlinformation for configuring and releasing SL grants will be described.

FIG. 11 is a diagram illustrating an operation for reporting UEassistance information according to the present invention.

In operation S1110, a UE receives a system information block (SIB)including system information associated with V2X from an eNB (E-UTRAN).The SIB may be defined as a new SIB. In FIG. 11, the SIB may be calledan SIB V2X. However, an SIB including system information related to V2Xmay be referred to using different terminologies other than SIB V2X. Forexample, the SIB V2X may be called SIB21, SIB22, or the like, to bedistinguished from a legacy SIB.

A UE that receives an SIB V2X may recognize that datatransmission/reception for a V2X service is allowed within the servicearea of a corresponding eNB. Also, the UE may determine V2X-relatedparameters to be used for the V2X service. The V2X-related parametersmay include the transmission power to be transmitted through a PC5 link,information indicating whether it is allowed to set mode 2 (i.e., a modein which a UE autonomously selects a radio resource of the PC5 link forV2X) and/or an exceptional mode, information associated with thetransmission and/or reception resource set (i.e., a resource pool)usable in a set mode, and the like.

In the case when a UE is set to have an RRC connection with an eNB andoperates based on mode 1 (i.e., a mode in which an eNB controls a radioresource of the PC5 link for V2X), when a condition for the UE todetermine that the connection with the eNB has a problem is satisfied,or when a condition for the UE to declare radio link failure issatisfied, the exceptional mode may be a mode that temporarily allowsthe UE to autonomously select a radio resource when the UE starts an RRCreconfiguration procedure. The exceptional mode is a mode thattemporarily allows the UE to autonomously configure radio resources.Subsequently, when a resource selection mode is not changed by the eNBand the condition that enables the UE to operate based on theexceptional mode is released, the exceptional mode is switched to mode 1again.

Also, the SIB V2X may include information associated with a plurality ofSL SPS configurations of a UE. In this instance, an eNB may not be awareof characteristics of SL communication performed between UEs. Thus, theeNB may receive, from a UE, information to be used for inferring the SLresource pattern required by the current UE, in order to determine theSL resource pattern required by the current UE for each of the pluralityof SL SPS configurations.

As described above, the UE assistance information(UEAssistanceInformation) in operation S1120 may include informationthat the UE provides to the eNB for SL communication. The informationthat the UE provides to the eNB may be V2X service information.

For example, V2X service information that is currently activated may beprovided to the eNB. V2X service information may include thetransmission of a Basic Safety Message (BSM) including informationrelated to the safety of a vehicle, or the transmission of a CooperativeAwareness Message (CAM) including state information (e.g., time,location, movement state, and the like) of a vehicle in an intelligenttraffic network system. Two or more services may be activated at thesame time, and thus a plurality of pieces of V2X service information maybe included in report information.

An eNB that receives V2X service information from a plurality of UEs (orvehicles) may determine an appropriate SL SPS out of the SL SPSs thatare currently configured for each of the UEs. When an appropriate SL SPSconfiguration for supporting a currently required V2X service does notexist among the SL SPS configuration information configured for each UE,the eNB may determine the configuration of an additional SL SPS.

According to an embodiment of the present invention, a separate RadioNetwork Temporary Identity (RNTI) may be used for SL SPS. The separateRNTI may be defined as an SPS SL-RNTI.

Here, when a plurality of SL SPS configurations exist for a single UE,an SPS SL-RNTI may be allocated to each of the plurality of SL SPSconfigurations. That is, the eNB may randomly select, as an SPS SL-RNTIvalue, one of the values in the range defined as shown in Table 1provided below, and may configure a single SPS SL-RNTI for each SL SPSconfiguration. That is, the eNB may inform a UE in advance of an SPSSL-RNTI value mapped for each SL SPS configuration, through an RRCmessage or the like.

TABLE 1 Value (hexa-decimal) RNTI 0000 N/A 0001-003C RA-RNTI, C-RNTI,Semi-Persistent Scheduling C-RNTI, Semi-Persistent Scheduling SL-RNTI,Temporary C-RNTI, eIMTA-RNTI, TPC-PUCCH-RNTI, TPC-PUSCH-RNTI andSL-RNTI, G-RNTI 003D-FFF3 C-RNTI, Semi-Persistent Scheduling C-RNTI,Semi-Persistent Scheduling SL-RNTI, eIMTA- RNTI, Temporary C-RNTI,TPC-PUCCH-RNTI, TPC-PUSCH-RNTI and SL-RNTI, G-RNTI FFF4-FFF9 ReservedFFFA SC-N-RNTI FFFB SC-RNTI FFFC CC-RNTI FFFD M-RNTI FFFE P-RNTI FFFFSI-RNTI

An SPS SL-RNTI may be used for determining SL SPS resource controlinformation that the eNB allocates for each SL SPS configuration. Forexample, the UE determines an SL SPS configuration to which controlinformation (i.e., SL SPS activation/deactivation indicatorinformation), which indicates SL SPS activation or deactivation and isreceived through a PDCCH/EPDCCH DCI or MAC CE, is to be applied, basedon an SPS SL-RNTI value. When the SL SPS activation/deactivationindication information indicates activation, the UE may store SL grantinformation provided through the PDCCH/EPDCCH DCI or MAC CE, and maydetermine that an SL grant is configured.

SL grants may be configured through the following procedure based on theRRC configuration information.

An example in which SL SPS activation/deactivation indicationinformation is provided through a PDCCH/EPDCCH will be described.

When SL SPS activation/deactivation indication information in a receivedPDCCH/EPDCCH indicates activation, a UE stores SL grant informationprovided through the PDCCH/EPDCCH and determines that an SL grant isconfigured.

DCI included in the PDCCH/EPDCCH is DCI for an SL newly introduced forvehicle communication, and SL SPS activation/deactivation indicationinformation may be included in the DCI. For example, when the SL SPSactivation/deactivation indication information is ‘1’, this indicatesactivation. When the SL SPS activation/deactivation indicationinformation is ‘0’, this indicates deactivation (SL grant release).

In Table 1, a PDCCH/EPDCCH including DCI for the SL and an SLSPS-related field may be available only when it is Cyclic RedundancyCheck (CRC), scrambled (or masked) with an SPS SL-RNTI.

Next, an example in which SL SPS activation/deactivation indicationinformation is provided through a MAC CE will be described.

To obtain information transmitted through the MAC CE, a UE may determinescheduling information associated with the MAC CE (e.g., physicalresource information to which a Physical Downlink Shared Channel (PDSCH)including a MAC CE is mapped) through PDCCH/EPDCCH DCI. A PDCCH/EPDCCHincluding scheduling information associated with the MAC CE may bescrambled/masked with a C-RNTI, and a UE may decode the PDCCH/EPDCCHbased on the C-RNTI. Here, the PDCCH/EPDCCH DCI including the schedulinginformation associated with the MAC CE may be PDCCH/EPDCCH DCI includingDL grant information (or DL assignment information) that schedules adownlink transmission from an eNB to a UE, unlike the above describedPDCCH/EPDCCH DCI including SL activation/deactivation information and/orSL grant information. That is, the UE that decodes the PDCCH/EPDCCH DCIincluding the DL grant information may receive a MAC CE transmittedthrough a PDSCH on a resource indicated by the DL grant information, maydeliver the received MAC CE to a MAC layer, and may determine thecontents thereof.

The SL SPS activation/deactivation indication information may betransmitted through a MAC CE. The MAC CE information may be configuredas a message having a variable length of 16 to 72 bits included in a MACpayload, or may be configured as a message having a fixed length of 20,24, 28, or 32 bits. Alternatively, the MAC CE information may betransmitted together with a corresponding MAC subheader, and the MACsubheader may be included in the MAC header of a MAC PDU. A MAC PDUformat according to the present invention will be described in detailwith reference to FIGS. 12 to 16.

Through Logical Channel ID (LCD) information included in the MACsubheader, a UE may determine whether a corresponding MAC CE is SL SPSactivation/deactivation indication information. For example, when anLCID value is ‘10111’, this may indicate SL SPS activation. When theLCID value is ‘10110’, this may indicate SL SPS deactivation.

16 bits of the message included in the MAC payload may have an SPSSL-RNTI value. Accordingly, a UE may determine an SL SPS configurationto which activation or deactivation is to be applied from among aplurality of SL SPS configurations, based on the SPS SL-RNTI.

Additionally, SL grant information having a length of 16, 20, or 24 bitsmay be included in the MAC CE. Alternatively, the length of the SL grantinformation may have a length of a multiple of 8.

Table 2 illustrates an example of information included in SL grant. TheSL grant information as shown in Table 2 may be included in the DCI of aPDCCH/EPDCCH, or may be included in a MAC CE. For example, the SL grantmay correspond to DCI format 5.

TABLE 2 DCI contents Field size Resource for PSCCH 6 Group destinationID 8 Timing advance indication 11  MCS (Modulation and coding scheme) 5TPC command for PSCCH and PSSCH 1 Frequency hopping flag 1 Resourceblock assignment and ┌log₂ (N_(RB) ^(SL) (N_(RB) ^(SL) + 1)/2)┐ hoppingresource allocation Time resource pattern 7 Total size (bit) 39 + ┌log₂(N_(RB) ^(SL) (N_(RB) ^(SL) + 1)/2)┐

The DCI content fields of Table 2 may be arranged from Most SignificantBit (MSB) to Least Significant Bit (LSB), but field arrangements are notlimited thereto. Also, some or all of the DCI content fields of Table 2may be included as SL grant information, an additional field that is notincluded in Table 2 may be further included, and the sequence in whichthe fields are listed may not be limited to this sequence.

The SL grant in the example of Table 2 may include a 6-bitResource-for-PSCCH field, an 8-bit Group destination ID field, an 11-bitTiming Advance Indication field, a 5-bit Modulation-and-Coding-Scheme(MCS) field, a 1-bit TPC-command-for-PSCCH-and-PSSCH field, a 1-bitfrequency-hopping-flag field, a ┌log₂(N_(RB) ^(SL)(N_(RB)^(SL)+1)/2┐-bitResource-block-assignment-and-hopping-resource-allocation field, and a7-bit time-resource-pattern field. In this instance, the size of the SLgrant may be 39+┌log₂(N_(RB) ^(SL)(N_(RB) ^(SL)+1)/2┐.

Here, N_(RB) ^(SL) may be determined based on a bandwidth supported by acorresponding system. For example, in an LTE system, N_(RB) ^(SL) may begiven as one of the values in the range of 6 through 100. The value mayindicate the maximum number of resource blocks (RB) that are allocablefor a V2X service in the corresponding system. An eNB in thecorresponding system may report the same to all UEs through systeminformation using a broadcast transmission scheme. The maximum number ofRBs may be expressed using an index of an RB resource configured for V2Xservice. For example, in a system having a bandwidth formed of 100consecutive RBs based on the frequency axis, the index of an RB existingin the lowest frequency band may be set to 0 and the index of an RBexisting in the highest frequency band may be set to 99. In thisinstance, RB resources configured for the V2X service may be expressedas RB indices x to y, and information actually reported to a UE mayinclude only x and y information. In this instance, x and y are integersthat are greater than or equal to 0 and less than or equal to 99, and xis an integer that is always smaller than y. Therefore, the maximumnumber of RBs may be calculated based on y-x.

When it is assumed that V2X data transmitted through a PC5 interface isalways in the broadcast form, a group destination ID field may beexcluded from the DCI contents.

Also, because a UE may receive resource allocation informationassociated with SL SPS in the state in which the UE is connected to aneNB, the UE may already obtain timing-advance-related information fromthe eNB. Therefore, the timing-advance-indication field may be excludedfrom the DCI contents.

Further, an eNB may not dynamically react to control transmission powerin view of a characteristic of SPS, and thus the effect of transmissionpower control by the eNB may be insignificant. Therefore, theTPC-command-for-PSCCH-and-PSSCH field may be excluded from the DCIcontents.

FIGS. 12 through 16 are diagrams illustrating the configuration of a MACPDU according to the present invention.

A MAC PDU may include a MAC header and a MAC payload. The MAC header mayinclude one or more MAC subheaders. The MAC payload may include one ormore MAC SDUs (or MAC CEs), and may further include padding as needed.Here, one MAC subheader corresponds to a MAC SDU (or MAC CE) or onepadding. That is, a plurality of MAC subheaders may be arranged in thesame order as the sequence in which MAC SDUs (or MAC CEs) and paddingsare arranged.

A normal MAC subheader may include six header fields R/R/E/LCID/F/L asshown in FIGS. 12 and 13, and the last MAC subheader may include fourheader fields R/R/E/LCID as shown in FIG. 14. FIG. 14 illustrates anexample of the format of a MAC CE.

In the examples of FIGS. 12 through 16, Oct denotes an octet and isconfigured in order Oct1, Oct2, Oct3, . . . , and the like.

R denotes a reserved bit.

E denotes whether another subheader exists in the MAC header after acorresponding subheader. When the value of E bit is ‘1’, this indicatesthat another subheader exists. When the value of E bit is ‘0’, a MACSDU, a MAC CE, or a padding starts from a subsequent bit.

An LCID may have a value indicating a type of a MAC CE or the logicalchannel of a MAC SDU corresponding to a MAC subheader. According to anembodiment of the present invention, the value of a LCID of a MACsubheader indicates whether MAC CE information corresponding to the MACsubheader is for SL SPS activation or for SL SPS deactivation. Forexample, when the LCID value is ‘10111’, this may indicate SL SPSactivation. When the LCID value is ‘10110’, this may indicate SL SPSdeactivation.

F denotes a bit indicating the size of an L field. When the value is‘0’, this indicates that a 7-bit L field exists as shown in FIG. 12.When the value is ‘1’, a 15-bit L field exists as shown in FIG. 13.

An L field may have a value indicating the size of a MAC SDU (or MAC CE)corresponding to a MAC subheader.

A MAC SDU (or MAC CE) as shown in FIG. 15 may include SL grantinformation and SPS SL-RNTI information.

An SL grant may include various fields as described in Table 2. Althoughit is simply expressed as SL grant in FIG. 15, this may indicate one ormore pieces of SL grant information and SL SPS activation/deactivationindication information.

An SPS SL-RNTI may have an SPS SL-RNTI value that is mapped to one of aplurality of SL SPS configurations. That is, a UE may determine an SLSPS configuration which SL grant information is related to, based on theSPS SL-RNTI value included in the MAC SDU (or MAC CE). Here, the orderof the SL grant and the SPS SL-RNTI may not be limited, and the SPSSL-RNTI may be located before or after the SL grant.

When the size of the SL grant in FIG. 15 is variable, a MAC subheaderfrom FIG. 12 or 13 may be used. When the size of the SL grant in FIG. 15is fixed, a UE may be aware of the size of a MAC SDU (or MAC CE)including the SL grant, without using an L (length) filed in the MACsubheader, and thus a MAC subheader from FIG. 14 may be used.

An additional embodiment of the present invention allocates a single SPSSL-RNTI to each UE, instead of allocating the same to each SL SPSconfiguration. That is, an eNB may randomly select one of the values inthe range defined as shown in Table 1 as an SPS SL-RNTI value, and mayconfigure a single SPS SL-RNTI for each UE.

Here, a plurality of SL SPS configurations exist for a single UE, andindex indicators for distinguishing the plurality of SL SPSconfigurations may be included in the corresponding SL SPS configurationinformation (e.g., RRC messages). The index indicator (“SL SPS indexindicator”) may be expressed as, for example, an SL_SPS_Index, and mayhave an integer value. The value of the SL_SPS_Index may be given as,for example, one of the values in the range of 0 through 7. That is,eight different SL SPS configurations may be configured for a single UE,and activation or deactivation of the eight SL SPS configurations may beindividually indicated. The maximum number of SL SPS configurations thatare allowed to be activated at the same time, 8, is equal to the maximumnumber of HARQ processes configurable in an LTE FDD system, because theSL SPS configuration activated at the same time may need to transmitdata through distinguished Hybrid Automatic Repeat reQuest (HARQ)processes. However, when the maximum number of HARQ processesconfigurable in a next generation mobile communication system has adifferent value, the maximum number of SL SPS configurations may bechanged and defined as the corresponding value. For example, when a timeperiod during which a single HARQ operation is performed is defined as Xms, the maximum number of HARQ processes may be defined by the maximumnumber of Time-To-Intervals (TTI) definable in X ms. A link that definesthe maximum number of HARQ processes may be determined based on eitherthe uplink and the downlink of a corresponding mobile communicationsystem, or may be determined for each of the uplink and the downlink. Asidelink that is a D2D communication link may have a different valuebased on a link through which transmission is to be performed from amongeither the uplink or the downlink.

The SL_SPS_index value may be provided through PDCCH/EPDCCH DCI or maybe provided through a MAC CE.

Table 3 shows an example of setting the value of a predetermined fieldfor each DCI format, for the validation of an SPS activationPDCCH/EPDCCH. According to the present invention, a predetermined fieldin a DCI format of the SPS activation PDCCH/EPDCCH may be reused, or anew field will be added and used as an SL_SPS_index. The SPS activationPDCCH/EPDCCH is scrambled with an SPS SL-RNIT configured for each UE,and is transmitted. This indicates that the SPS activation PDCCH/EPDCCHis for SL SPS.

Table 3 provided below illustrates an example of reusingModulation-and-coding-scheme-and-redundancy-version of DCI format 0 anda Modulation-and-coding-scheme field of DCI format 1/1A, for indicatingan SL_SPS_index value.

TABLE 3 DCI format DCI format 0 DCI format 1/1A 2/2A/2B/2C/2D TPCcommand for set to ‘00’ N/A N/A scheduled PUSCH Cyclic shift DM RS setto ‘000’ N/A N/A Modulation and coding MSB is set to ‘0’ and N/A N/Ascheme and redundancy left 4 bits set to version ‘SL_SPS_Index’ HARQprocess number N/A FDD: set to ‘000’ FDD: set to ‘000’ TDD: set to‘0000’ TDD: set to ‘0000’ Modulation and coding N/A MSB is set to ‘0’and For the enabled scheme left 4 bits set to transport block:‘SL_SPS_Index’ MSB is set to ‘0’ Redundancy version N/A set to ‘00’ Forthe enabled transport block: set to ‘00’

Although the example of Table 3 illustrates a method for allocating fourbits as an SL_SPS_index, a method for allocating three bits from an LSBas an SL_SPS_Index may be used for DCI format 0 and 1/1A.

Alternatively, an SL_SPS_index field and a new field indicating SL SPSactivation or deactivation may be further included in legacy DCI format5 indicating an SL grant. Therefore, fields in DCI format 5 may be asfollows.

-   -   Resource for PSCCH—6 bits    -   TPC command for PSCCH and PSSCH—1 bit    -   Frequency hopping flag—1 bit    -   Resource block assignment and hopping resource allocation        -   In the case of PSSCH hopping, (┌log₂(N_(RB) ^(SL)(N_(RB)            ^(SL)+1)/2┐−N_(SL) _(_) _(hop)) bits        -   Otherwise, (┌log₂(N_(RB) ^(SL)(N_(RB) ^(SL)+1)/2┐) bits    -   Time resource pattern—7 bits    -   SL SPS activation/deactivation—1 bit    -   SL_SPS_Index—3 bits

Alternatively, a new DCI format for SL SPS, which is different from thelegacy DCI format, may be defined. The DCI format may include one ormore of the SL grant fields in Table 2, and may further include anSL_SPS_Index field and a new field indicating SL SPS activation ordeactivation.

As an additional method of providing SL SPS activation controlinformation through a MAC CE, a method of transmitting an SL_SPS_Indexfield instead of an SPS SL_RNTI field may be used.

Alternatively, as illustrated in FIG. 16, a MAC SDU (or MAC CE) mayinclude SL_SPS_Index information and SL grant information.

Specifically, as illustrated in FIG. 16, a single octet may include a3-bit SL_SPS_Index field and 5 pieces of R-bit. Although it is simplyexpressed as SL grant in FIG. 16, this may indicate one or more piecesof SL grant information and SL SPS activation/deactivation indicationinformation. Also, the order of the SL_SPS_Index and the SL grant is notlimited, and the SPS SL-RNTI may be located before or after the SLgrant. When the size of the SL grant in FIG. 16 is variable, a MACsubheader from FIG. 12 or 13 may be used. When the size of the SL grantin FIG. 16 is fixed, a UE may be aware of the size of a MAC SDU (or MACCE) including the SL grant, without using an L (length) filed from theMAC subheader, and thus a MAC subheader from FIG. 14 may be used.

Although a plurality of SL SPS configurations are determined for asingle UE at the same time, as described in the above examples, theremay be a case in which another V2X service is added or a resource fordata transmission is additionally required. In this instance, although aresource exists which is allocated to an SL SPS configuration that hasalready been activated for transmission (or broadcasting) to anidentical destination group, additional resource allocation may beneeded temporarily or during a predetermined period of time.Alternatively, a data transmission having a period shorter than an SLSPS period may be required during a predetermined period of time.

In the above described examples of the present invention, a plurality ofSL SPS configurations (e.g., SL SPS configurations #0, #1, #2, #3, #4,#5, #6, and #7) may exist for a single UE. In the state in which some(e.g., SL SPS configuration #1) of the plurality of SL SPSconfigurations are activated, when other SL SPS configurations (e.g., SLSPS configuration #3) are activated, a plurality of SL SPSconfigurations (e.g., SL SPS configurations #1 and #3) may be activated.

Meanwhile, a plurality of SL SPS configurations may not be activated atthe same time, and the activation of a single SL SPS configuration maybe allowed at an arbitrary point in time. In this instance, to allocatean additional resource to a resource that has been allocated for acurrently activated SL SPS configuration, an SL grant associated withthe already activated SL SPS configuration is released (SL SPSdeactivation) and an SL grant is provided through resource allocationthrough a PDCCH/EPDCCH DCI or MAC CE. Therefore, new SL SPSconfigurations may be determined. Every time that an additional resourceallocation is needed, an SL grant that has already been activated isreleased (SL SPS deactivation) and a new SL SPS configuration may bedetermined by providing control information through a PDCCH/EPDCCH DCIor MAC CE. In this instance, a message for releasing the alreadyactivated SL grant (or SL SPS deactivation) needs to be transmitted, andthus signaling overhead may be increased.

To overcome the increase of the signaling overhead, an additionalexample of the present invention defines that a new SL SPS activationindication implicitly indicates the deactivation of an already activatedSL SPS configuration.

For example, in the state in which a first SL SPS configuration isactivated, a UE that receives control information for activating asecond SL SPS configuration (e.g., control information provided throughPDCCH/EPDCCH DCI or MAC CE as shown in the above examples of the presentinvention) may deactivate the first SL SPS configuration at a point intime when the second SL SPS configuration is activated, although the UEwill not receive deactivation indication information associated with thefirst SL SPS configuration.

Here, the first SL SPS configuration may be an SL SPS configurationcorresponding to the value of a first SPS SL-RNTI, and the second SL SPSconfiguration may be an SL SPS configuration corresponding to the valueof a second SPS SL-RNTI. Alternatively, the first SL SPS configurationmay be an SL SPS configuration corresponding to the value of a firstSL_SPS_index, and the second SL SPS configuration may be an SL SPSconfiguration corresponding to the value of a second SL_SPS_index.

Different (or independent) SL SPS resources may be allocated to aplurality of SL SPS configurations (e.g., SL SPS configuration #0, #1,#2, #3, #4, #5, #6, and #7) configured for a single UE. In thisinstance, according to the above described example, through the implicitdeactivation of an already-activated SL SPS configuration (e.g., SL SPSconfiguration #1) and the activation of a new SL SPS configuration(e.g., SL SPS configuration #3), an SL SPS resource allocated to the UEmay be changed. When the activation of the plurality of SL SPSconfigurations at the same time is supported, and SL SPS configuration#3 is activated additionally in the state in which SL SPS configuration#1 is activated, this leads to a result different from the resultobtained when resources corresponding to a union of SL SPS resourcesallocated to SL SPS configurations #1 and #3 are allocated to the UE.

One (e.g., SL SPS configuration #3) of a plurality of SL SPSconfigurations (e.g., SL SPS configurations #0, #1, #2, #3, #4, #5, #6,and #7) configured for a single UE may include all of anotherconfiguration (e.g., SL SPS configuration 31). In this instance, the SLSPS resources which are allocated to the UE as a result of the implicitdeactivation of an already-activated SL SPS configuration (e.g., SL SPSconfiguration #1) and the activation of a new SL SPS configuration(e.g., SL SPS configuration #3), are the same as the SL SPS resourceswhich are allocated to the UE when the activation of a plurality of SLSPS configurations at the same time is supported and when SL SPSconfiguration #3 is additionally activated in the state in which SL SPSconfiguration #1 is already activated.

That is, depending on the method of allocating an SL SPS resourcecorresponding to an SL SPS configuration, a scheme of allowing theactivation of a plurality of SL SPS configurations at the same time anda scheme of allowing the activation of a single SL SPS at an arbitrarypoint in time are different from each other. However, SL SPS resourcesallocated to a UE, as a result of the scheme, may be operated in thesame manner.

Also, when an SL grant configured by SL SPS is released according toFIG. 9, FIG. 10, and the condition of the ‘implicitReleaseAfterSL’ valueis not configured, the release of the SL grant configured by SL SPS forV2X may be reported through a UE assistance information reportingprocedure which has been described in FIG. 11. Here, when a plurality ofSL SPS configurations are activated, at least one SL SPS from which theSL grant is released and of which SL grant release is reported may existat the same time. Accordingly, information indicating an SL SPSconfiguration from which the SL grant is released may be included in asignal in the UE assistance information reporting procedure and may betransmitted to an eNB. Here, the information indicating an SL SPSconfiguration from which the SL grant is released may be an SPS SL-RNTI,which has been described in an embodiment of the present invention, oran SL_SPS_index value, which has been described in another embodiment ofthe present invention. A signal for reporting the UE assistanceinformation may be defined in the RRC layer, which is Layer 3 signaling,because a change in the information related to V2X service and thegeneration of an SL SPS configuration from which the SL grant isreleased do not frequently occur.

In the situation in which a plurality of SL SPS configurations areactivated, at least one SL SPS from which an SL grant release isreported may exist at the same time. In this instance, an SPS SL-RNTI orSL_SPS_Index value corresponding to the SL SPS from which the SL grantrelease is reported may be configured as a list in the RRC signaling,and may be transmitted to an eNB.

In the case of a system where the occurrence of an SL SPS configurationfrom which an SL grant is released is more frequently observed than thechange of V2X service-related information because the number of SL SPSconfigurations is high, the system may configure SL SPS configurationinformation from which an SL grant is released, in the form of a MAC CEthat is a MAC layer signaling, separately from the V2X service-relatedinformation change report, and the system may transmit the same. In thisinstance, a UE may indicate that the corresponding MAC CE information isinformation indicating the release of an SL grant by SL SPS, through anLCID value indicating SL grant release, and may transmit an SPS SL-RNITor SL_SPS_Index field through the MAC CE information in a payload. TheSPS SL-RNTI or SL_SPS_index field, which is a field remaining afterexcluding the SL grant field from the MAC CE of FIG. 15 and FIG. 16, maybe included in the MAC CE in the payload.

In the situation in which a plurality of SL SPS configurations areactivated, at least one SL SPS from which an SL grant is released andreported, may exist at the same time. Therefore, to indicate the same, aplurality of SP SL-RNTI or SL_SPS_Index fields may be included in theMAC CE (which corresponds to a single LCID) in the payload, and may havea variable length. Therefore, an LCID format may have the formatillustrated in FIG. 12 or in FIG. 13 to support a variable length. Inthe case of the SL_SP S_index field, the length is not a multiple of 8.Accordingly, how many SL_SPS_Index fields are included may not beaccurately identified through the L field. Therefore, to indicate thesame, a 3-bit indicator indicating the number of SL SPS index fields maybe included in the first location of the MAC CE (which corresponds to asingle LCD) in the payload. In this instance, the length of the MAC CEmay be identified through the indicator that indicates the number ofSL_SPS_Index fields, and thus the LCID format may have the formatillustrated in FIG. 14, which supports a fixed length.

As another example, only an SPS SL_RNTI or SL_SPS_Index field may beincluded in the MAC CE (which corresponds to a single LCD) in thepayload. Therefore, the LCID format may comply with the format in FIG.14 that supports a fixed length, and may include a plurality of MAC CEsin a single MAC PDU when a plurality of events occur that need to bereported.

FIG. 17 is a flowchart illustrating the operations of an eNB and a UEaccording to the present invention.

Before performing operation S1710 in FIG. 17, an eNB provides a UE withV2X-related system information in operations S1110 and S1120 in FIG. 11,and the UE provides an eNB with information required for beginning thetransmission/reception of V2X data on the PC5 link in the form of V2Xservice information, based on the V2X-related system information. TheV2X service information may include information related to BSM, CAM, andthe like as described in FIG. 11, and may further include information,such as a V2X service list, an SL BSR, a V2X BSR, or the like. Suchinformation may be provided to the eNB at the same time or at differentpoints in time.

In operation S1710, the eNB determines that the UE requires a periodicSL data transmission/reception such as a vehicle communication service,based on the V2X service-related information received from the UE, andaccordingly, the eNB may determine a plurality of SL SPS configurationsto be configured for the corresponding UE.

In operation S1720, the eNB transmits an RRC reconfiguration messageincluding SL SPS configuration information to the UE. Here, a pluralityof SL SPS configurations may be configured for a single UE, and SL SPSconfiguration information may include information for allocatingindividual identification information (e.g., SPS SL-RNTI orSL_SPS_Index) with respect to the plurality of SL SPS configurations.

For example, when each UE has a single SPS SL-RNTI, the SL SPSconfiguration information may be defined by the structure of Table 4. Aplurality of SL SPS configurations are configured in the form of a list,and a single SPS SL-RNTI is configured for all of the configurations inthe list.

TABLE 4 SL_SPS-Config ::= SEQUENCE {  semiPersistSchedSL-RNTI C-RNTI, sps-ConfigSLList SEQUENCE (SIZE (1..maxSL_HARQ)) OF SPS-ConfigSL }SPS-ConfigSL ::= CHOICE {  release NULL,  setup SEQUENCE { SL_SPS_IndexINTEGER (0..7), semiPersistSchedIntervalSL ENUMERATED { 1, 2, 3, 4, 6,8, 12, 16, 32, 64, spare6, spare5, spare4, spare3, spare2, spare1},implicitReleaseAfterSL ENUMERATED (e1, e2, e3, e4, e8), ]]  } }

As another example, when each SL SPS configuration has a single SPSSL-RNTI, the SL SPS configuration information may be defined by thestructure of Table 5.

TABLE 5 SL_SPS-Config ::= SEQUENCE {  sps-ConfigSLList SEQUENCE (SIZE(1..maxSL_HARQ)) OF SPS-ConfigSL } SPS-ConfigSL ::= CHOICE {  releaseNULL,  setup SEQUENCE { semiPersistSchedSL-RNTI C-RNTI,semiPersistSchedIntervalSL ENUMERATED { 1, 2, 3, 4, 6, 8, 12, 16, 32,64, spare6, spare5, spare4, spare3, spare2, spare1},implicitReleaseAfterSL ENUMERATED {e1, e2, e3, e4, e8}, ]]  } }

In operation S1730, the eNB transmits SL SPS-related control informationto the UE. The SL SPS-related control information may include one ormore of SL SPS activation/deactivation indication information and SLgrant information. For example, the eNB may determine a point in timewhen the UE requires a periodic SL data transmission/reception based oninformation received from the UE, such as SL BSR, or the like, and mayprovide SL SPS-related control information to the UE at the determinedpoint in time. Also, the SL SPS-related control information may beprovided through a PDCCH/EPDCCH DCI or a MAC CE. The SL SPS-relatedcontrol information may include at least one piece of the information inTable 2.

In operation S1740, the UE determines the SL SPS-related controlinformation from the eNB.

For example, the UE attempts to receive a PDCCH/EPDCCH based on each SPSSL-RNTI value of the SL SPS configuration information configured throughthe RRC reconfiguration procedure or the like in operation S1720, inorder to determine whether a PDCCH/EPDCCH DCI, which is transmitted bythe eNB and which includes activation indication information associatedwith a predetermined SL SPS configuration, exists. When a PDCCH/EPDCCHthat is scrambled or masked with an SPS SL-RNTI value is successfullydecoded, the UE may determine the SL SPS-related control information(e.g., one or more of the activation indication information and an SLgrant for an SL SPS configuration) included in the DCI received throughthe corresponding PDCCH/EPDCCH.

Also, the UE may attempt to receive a PDCCH/EPDCCH based on a C-RNTIvalue, may receive a PDSCH on a PDSCH resource indicated by DCI includedin the PDCCH/EPDCCH, and may determine SL SPS-related controlinformation for a predetermined SL SPS configuration (e.g., one or moreout of the activation indication information and the SL grant for an SLSPS configuration) based on the SPS SL-RNTI information or theSL_SPS_index information included in a MAC CE received through thePDSCH.

When the UE determines that the SL SPS-related control informationprovided from the eNB is for the predetermined SL SPS configuration, theUE may activate the predetermined SL SPS configuration based on the SLSPS-related control information in operation S1750. The activation ofthe SL SPS configuration may include an operation for determining aresource for transmitting/receiving SL SPS data based on the SL grantinformation included in the SL SPS-related control information receivedin operation S1730. Also, the activation of the SL SPS configuration mayinclude the operation for activating a new SL SPS configuration inaddition to an SL SPS configuration which has already been activated,thereby activating a plurality of SL SPS configurations. Alternatively,when the activation of only a single SL SPS configuration is supportedat an arbitrary point in time, the activation of the SL SPSconfiguration may include an operation for deactivating an SL SPSconfiguration which has already been activated by the activation of theSL SPS configuration, and for activating a new SL SPS configuration.

When the UE determines that the SL SPS-related control informationreceived in operation S1730 includes information indicating thedeactivation of a predetermined SL SPS configuration in operation S1740,the UE may deactivate the predetermined SL SPS configuration inoperation S1750. Alternatively, in the case in which the activation ofonly a single SL SPS configuration is supported at an arbitrary point intime, when the UE determines activation indication informationassociated with a new SL SPS as opposed to the predetermined SL SPSconfiguration that is currently activated, instead of determining theexplicit indication of the deactivation of the predetermined SL SPSconfiguration, the UE may deactivate the SL SPS configuration that iscurrently activated.

When the predetermined SL SPS configuration is activated in operationS1750, the UE transmits/receives SL SPS data to/from another UE on anactivated SL SPS resource in operation S1760. For example, the SL SPSdata transmission/reception may include the transmission of data for aV2X service to another UE through a PC5 radio link.

In some embodiments, a method of controlling Semi-Persistent Scheduling(SPS) for a user device may be performed by a base station. The methodincludes generating, by the base station, SL SPS configurationinformation for the user device, configuring a radio resource control(RRC) message comprising the SL SPS configuration information, andtransmitting, by the base station and to the user device, the RRCmessage. The SL SPS configuration information comprises: an SL SPS radionetwork temporary identifier (RNTI) for the user device; and SL SPSindex information to indicate a plurality of SL SPS configurations forthe user device.

The base station may transmit to the user device a Physical DownlinkControl Channel (PDCCH) comprising downlink control information (DCI),the PDCCH being scrambled by the SL SPS RNTI for the user device.

The base station may scramble a PDCCH by using the SL SPS RNTI for theuser device, the PDCCH comprising activation information about one ofthe plurality of SL SPS configurations for the user device. The SL SPSconfiguration information for the user device and the PDCCH scrambled bythe SL SPS RNTI enable the user device to operate an SL SPS associatedwith a direct communication between the user device and another userdevice.

The base station may set a3-bit value in a 3-bit field in the DCI. The3-bit field has an SL SPS index. The maximum quantity of the SL SPSconfigurations for the user device may be eight. In some configurations,the quantity of the SL SPS configurations for the user device may bemore than one but fewer than eight. The DCI may comprise a 3-bit fieldhaving an SL SPS index. Eight different SL SPS indexes may be indicatedby a 3-bit value of the 3-bit field.

The DCI may comprise a 1-bit field indicating activation or deactivationof a SL SPS configuration associated with the SL SPS index. For example,“1” may indicate the activation and “0” may indicate the deactivation(or vice versa). The base station may determine whether to activate anSL SPS configuration associated with the SL SPS index set in the 3-bitfield. Based on the determining whether to activate the SL SPSconfiguration, the base station sets a value in a 1-bit field in theDCI.

The SL SPS configuration information may further comprise an SL SPSinterval for one or more of the plurality of SL SPS configurations forthe user device. For example, the base station may determine a first SLSPS interval for a first one of the plurality of SL SPS configurationsfor the user device and a second SL SPS interval for a second one of theplurality of SL SPS configurations for the user device. The SL SPSconfiguration information further comprises the first SL SPS intervaland the second SL SPS interval.

The user device may be a vehicle capable of receiving the RRC messageand PDCCH from an evolved NodeB and directly communicating with anothermobile device. For example, the user device comprises one or more of: avehicle having a vehicle-to-vehicle (V2V) communication capability, avehicle having a vehicle-to-pedestrian (V2P) communication capability, avehicle having a vehicle-to-infrastructure (V2I) communicationcapability, or a vehicle having a vehicle-to-everything (V2X)communication capability.

The base station may determine a quantity of SL SPS configurations forthe user device, determine, based on the determined quantity of SL SPSconfigurations for the user device, a plurality of SL SPS configurationindex indicators for the plurality of SL SPS configurations for the userdevice, and configure the plurality of SL SPS configurations for theuser device. Each SL SPS configuration for the user device comprises acorresponding one of the plurality of SL SPS configuration indexindicators, and an SL SPS interval for the corresponding one of theplurality of SL SPS configuration indicators.

The base station may determine the plurality of SL SPS configurationindex indicators from predefined integer values.

A method of configuring a plurality of sidelink (SL) Semi-PersistentScheduling (SPS) for a user device may be performed by a base station.The method includes generating, by a base station, SL SPS configurationinformation for the user device; configuring a radio resource control(RRC) message comprising the SL SPS configuration information; andtransmitting, by the base station and to the user device, the RRCmessage. The SL SPS configuration information comprises: an SL SPS radionetwork temporary identifier (RNTI) for the user device; SL SPS indexinformation to indicate a plurality of SL SPS configurations for theuser device; a first SL SPS interval for a first SL SPS configurationfor the user device; and a second SL SPS interval for a second SL SPSconfiguration for the user device.

The base station may transmit, to the user device, a first PDCCHassociated with the first SL SPS configuration, the first PDCCH beingscrambled by the SL SPS RNTI for the user device. The base station mayalso transmit, to the user device, a second PDCCH associated with thesecond SL SPS configuration, the second PDCCH being scrambled by the SLSPS RNTI for the user device. The first PDCCH indicates a 3-bit SL SPSindex of the first SL SPS configuration for the user device, and thesecond PDCCH indicates a different 3-bit SL SPS index of the second SLSPS configuration for the user device.

A method of processing configuration information for Semi-PersistentScheduling (SPS) for a user device may be performed by a user device.The method includes receiving, by the user device and from a basestation, a radio resource control (RRC) message comprising SL SPSconfiguration information for the user device; receiving, by the userdevice, a Physical Downlink Control Channel (PDCCH) comprising downlinkcontrol information (DCI) and associated with the SL SPS RNTI; anddetermining, based on the PDCCH, control information of an SL SPSconfiguration for the user device. The SL SPS configuration informationcomprises: an SL SPS radio network temporary identifier (RNTI) for theuser device; and SL SPS index information to indicate a plurality of SLSPS configurations for the user device.

The user device may determine the control information of the SL SPSconfiguration for the user device, in response to determining that thePDCCH was scrambled by the SL SPS RNTI for the user device.

The user device may descramble the PDCCH by using the received SL SPSRNTI.

The user device may be a V2X UE and may activate, based on the SL SPSconfiguration information for the user device and the descrambled PDCCH,an SL SPS operation for a direct communication between the user deviceand another V2X UE,

The user device may determine, based on the received RRC message, aquantity of SL SPS configurations set for the user device.

The user device may determine, based on the received RRC message, aquantity of SL SPS configurations set for the user device, and determinean SL SPS index from a 3-bit field in the DCI, the 3-bit field havingthe SL SPS index.

The user device may determine, based on an activation indicator field inthe DCI, an activation or deactivation of a SL SPS configurationassociated with the SL SPS index, the activation indicator field being a1-bit field.

The user device may determine SL SPS intervals for the plurality of SLSPS configurations for the user device, wherein the SL SPS configurationinformation further comprises the SL SPS intervals for the plurality ofSL SPS configurations for the user device.

FIG. 18 is a diagram illustrating the configuration of a wireless deviceaccording to the present invention.

FIG. 18 illustrates a UE 100 that corresponds to an example of adownlink receiving device or an uplink transmitting device, andillustrates an eNB 200 that corresponds to an example of a downlinktransmitting device or an uplink receiving device. Although notillustrated in FIG. 18, another UE that performs V2X communication withthe UE 100 may exist. The configuration of the other UEs is similar tothat of the UE 100, and thus detailed descriptions thereof will beomitted.

The UE 100 may include a processor 110, an antenna unit 120, atransceiver 130, and a memory 140.

The processor 110 may process signals related to a baseband, and mayinclude a higher layer processing unit 111 and a physical layerprocessing unit 112. The higher layer processing unit 111 may processthe operations of a Medium Access Control (MAC) layer, a Radio ResourceControl (RRC) layer, or a higher layer that is higher than them. Thephysical layer processing unit 112 may process the operations of a PHYlayer (e.g., processing an uplink transmission signal or processing adownlink reception signal). The processor 110 may control the generaloperations of the UE 100, in addition to processing signals related to abaseband.

The antenna unit 120 may include one or more physical antennas, and maysupport MIMO transmission/reception when a plurality of antennas isincluded. The transceiver 130 may include a Radio Frequency (RF)transmitter and an RF receiver. The memory 140 may store informationprocessed by the processor 110, software, operating system,applications, or the like associated with the operations of the UE 100,and may include elements such as a buffer or the like.

The eNB 200 may include a processor 210, an antenna unit 220, atransceiver 230, and a memory 240.

The processor 210 processes signals related to a baseband, and mayinclude a higher layer processing unit 211 and a physical layerprocessing unit 212. The higher layer processing unit 211 may processthe operations of an MAC layer, an RRC layer, or a higher layer. Thephysical layer processing unit 212 may process the operations of a PHYlayer (e.g., processing a downlink transmission signal or processing anuplink reception signal). The processor 210 may control the generaloperations of the eNB 200, in addition to processing signals related toa baseband.

The antenna unit 220 may include one or more physical antennas, and maysupport MIMO transmission/reception when a plurality of antennas areincluded. The transceiver 230 may include an RF transmitter and an RFreceiver. The memory 240 may store information processed by theprocessor 210, software, operating system, applications, or the likeassociated with the operations of the eNB 200, and may include elementssuch as a buffer or the like.

The processor 110 of the UE 100 may be configured to implement theoperations of the UE, which have been described in all of theembodiments of the present invention.

For example, the physical layer processing unit 112 of the processor 110of the UE 100 may receive SL SPS configuration information receivedthrough an RRC message from the eNB and then deliver the same to thehigher layer processing unit 111. The physical layer processing unit 112may also demodulate information (e.g., SL SPS activation/deactivationindication information and/or SL grant information) received from theeNB through SL SPS configuration information PDCCH/EPDCCH DCI or MAC CE,and may deliver the same to the higher layer processing unit 111.

Alternatively, the higher layer processing unit 111 of the processor 110of the UE 100 may include an SL SPS configuration information processingunit 1811 and an SL SPS-related control information processing unit1812. The SL SPS configuration information processing unit 1811 maydetermine configuration information associated with a plurality of SLSPS configurations provided from the eNB through an RRC message, and maystore required information. The SL SPS-related control informationprocessing unit 1812 may determine information (e.g. SL SPSactivation/deactivation indication information and/or SL grantinformation) which is associated with a predetermined SL SPSconfiguration and is received from the eNB, and may store requiredinformation. Accordingly, the processor 110 may activate or deactivate apredetermined SL SPS configuration with respect to the UE 100, and maytransmit/receive SL SPS data to/from another UE through the physicallayer processing unit 112 on a resource allocated for the activated SLSPS configuration.

The processor 210 of the eNB 200 may be configured to implement theoperations of the eNB, which have been described in all of theembodiments of the present invention.

For example, the higher layer processing unit 211 of the processor 210of the eNB 200 may include an SL SPS configuration determining unit 1821and an SL SPS-related control information determining unit 1823. The SLSPS configuration determining unit 1821 may determine whether an SL SPSconfiguration is needed for a predetermined UE based on V2X serviceinformation or the like received from UE(s), and may determine one ormore SL SPS configurations to be configured for the predetermined UE.The SL SPS-related control information determining unit 1823 maygenerate information (e.g., SL SPS activation/deactivation indicationinformation and/or SL grant information) for the predetermined UE.

Also, the physical layer processing unit 212 of the processor 210 of theeNB 200 may transmit, to the UE 100, SL SPS configuration informationand SL SPS-related control information, which are delivered from thehigher layer processing unit 211. Also, the physical layer processingunit 212 may transmit a message to a UE, such as an SIB V2X or the like,which is delivered from the higher layer processing unit 211, and mayreceive V2X service information or the like from a UE to deliver thesame to the higher layer processing unit 211.

According to one or more embodiments of the present disclosure, an eNBis capable of supporting multiple SPS resource allocation schemes forradio resources for D2D communication, which are required when a UEperforms multiple V2X services and general cellular services, and thus,the number of repetitive control information transmissions performed bythe eNB may be reduced and the efficiency of the use of radio resourcesmay be increased.

What is claimed is:
 1. A method of controlling Semi-PersistentScheduling (SPS) for a user device, the method comprising: generating,by a base station, sidelink (SL) SPS configuration information for theuser device, wherein the SL SPS configuration information comprises: anSL SPS radio network temporary identifier (RNTI) for the user device;and SL SPS index information to indicate a plurality of SL SPSconfigurations for the user device; configuring a radio resource control(RRC) message comprising the SL SPS configuration information; andtransmitting, by the base station and to the user device, the RRCmessage.
 2. The method of claim 1, further comprising: transmitting, bythe base station and to the user device, a Physical Downlink ControlChannel (PDCCH) comprising downlink control information (DCI), the PDCCHbeing scrambled by the SL SPS RNTI for the user device.
 3. The method ofclaim 1, further comprising: scrambling, by the base station, a PhysicalDownlink Control Channel (PDCCH) by using the SL SPS RNTI for the userdevice, the PDCCH comprising activation information about one of theplurality of SL SPS configurations for the user device, wherein the SLSPS configuration information for the user device and the PDCCHscrambled by the SL SPS RNTI enable the user device to operate an SL SPSassociated with a direct communication between the user device andanother user device.
 4. The method of claim 2, further comprising:setting a value in a 3-bit field in the DCI, the 3-bit field having anSL SPS index, wherein a maximum quantity of the SL SPS configurationsfor the user device is eight.
 5. The method of claim 4, furthercomprising: determining, by the base station, whether to activate an SLSPS configuration associated with the SL SPS index set in the 3-bitfield; and setting, based on the determining whether to activate the SLSPS configuration, a value in a 1-bit field in the DCI, wherein the DCIcomprises the 1-bit field indicating activation or deactivation of theSL SPS configuration associated with the SL SPS index.
 6. The method ofclaim 1, further comprising: determining a first SL SPS interval for afirst one of the plurality of SL SPS configurations for the user device;and determining a second SL SPS interval for a second one of theplurality of SL SPS configurations for the user device, wherein the SLSPS configuration information further comprises the first SL SPSinterval and the second SL SPS interval.
 7. The method of claim 6,wherein the first SL SPS interval and the second SL SPS interval havedifferent intervals.
 8. The method of claim 1, wherein the user devicecomprises one or more of: a vehicle having a vehicle-to-vehicle (V2V)communication capability, a vehicle having a vehicle-to-pedestrian (V2P)communication capability, a vehicle having a vehicle-to-infrastructure(V2I) communication capability, or a vehicle having avehicle-to-everything (V2X) communication capability.
 9. The method ofclaim 1, wherein the generating the SL SPS configuration information forthe user device comprises: determining a quantity of SL SPSconfigurations for the user device; determining, based on the determinedquantity, a plurality of SL SPS configuration index indicators for theplurality of SL SPS configurations for the user device; and configuringthe plurality of SL SPS configurations for the user device, wherein eachSL SPS configuration for the user device comprises: a corresponding oneof the plurality of SL SPS configuration index indicators; and an SL SPSinterval for the corresponding one of the plurality of SL SPSconfiguration indicators.
 10. The method of claim 9, further comprisingdetermining the plurality of SL SPS configuration index indicators frompredefined integer values.
 11. A method of processing configurationinformation for Semi-Persistent Scheduling (SPS) for a user device, themethod comprising: receiving, by the user device and from a basestation, a radio resource control (RRC) message comprising sidelink (SL)SPS configuration information for the user device, wherein the SL SPSconfiguration information comprises: an SL SPS radio network temporaryidentifier (RNTI) for the user device; and SL SPS index information toindicate a plurality of SL SPS configurations for the user device;receiving, by the user device, a Physical Downlink Control Channel(PDCCH) comprising downlink control information (DCI) and associatedwith the SL SPS RNTI; and determining, based on the PDCCH, controlinformation of an SL SPS configuration for the user device.
 12. Themethod of claim 11, wherein the determining the control information ofthe SL SPS configuration for the user device comprises: in response todetermining that the PDCCH was scrambled by the SL SPS RNTI for the userdevice, determining the control information of the SL SPS configurationfor the user device.
 13. The method of claim 11, further comprising:descrambling, by the user device, the PDCCH by using the received SL SPSRNTI; and activating, based on the SL SPS configuration information forthe user device and the descrambled PDCCH, an SL SPS operation for adirect communication between the user device and anothervehicle-to-everything (V2X) user equipment (UE), wherein the user deviceis a V2X UE.
 14. The method of claim 11, further comprising:determining, based on the received RRC message, a quantity of SL SPSconfigurations set for the user device; and determining an SL SPS indexfrom a 3-bit field in the DCI, the 3-bit field having the SL SPS index,wherein a maximum quantity of the SL SPS configurations for the userdevice is eight.
 15. The method of claim 14, further comprising:determining, based on an activation indicator field in the DCI, anactivation or deactivation of a SL SPS configuration associated with theSL SPS index, the activation indicator field being a 1-bit field. 16.The method of claim 11, further comprising: determining SL SPS intervalsfor the plurality of SL SPS configurations for the user device, whereinthe SL SPS configuration information further comprises the SL SPSintervals for the plurality of SL SPS configurations for the userdevice.
 17. The method of claim 16, wherein a first one of the pluralityof SL SPS configurations for the user device and a second one of theplurality of SL SPS configurations for the user device have different SLSPS intervals.
 18. The method of claim 11, wherein the user devicecomprises one or more of: a vehicle having a vehicle-to-vehicle (V2V)communication capability, a vehicle having a vehicle-to-pedestrian (V2P)communication capability, a vehicle having a vehicle-to-infrastructure(V2I) communication capability, or a vehicle having avehicle-to-everything (V2X) communication capability.
 19. The method ofclaim 11, further comprising: activating or deactivating, based on thecontrol information of the SL SPS configuration for the user device, anSL SPS operation associated with the SL SPS configuration.
 20. Themethod of claim 11, further comprising: determining, based on thereceived RRC message, a plurality of SL SPS configuration indexindicators for the plurality of SL SPS configurations for the userdevice; and obtaining, from each of the plurality of SL SPSconfigurations set for the user device, a corresponding one of theplurality of SL SPS configuration index indicators, and an SL SPSinterval for the corresponding one of the plurality of SL SPSconfiguration indicators.